Risk groups and staging for neuroblastoma

Neuroblastoma risk groups

Doctors group children with neuroblastoma into risk groups. This is according to their risk of the cancer coming back after treatment. The risk groups are called:

• low risk

• intermediate risk

• high risk

The treatment your child has for their neuroblastoma depends on which risk group they are in. Doctors use the cancer stage as well as the child’s age and results of other tests to make a decision about treatment.

Staging neuroblastoma

The stage of a cancer tells you the size and whether it has spread. Knowing the stage can help your doctor decide on the right treatment. And it can help to predict the outcome (prognosis) after treatment. Doctors use the International Neuroblastoma Risk Group Staging System (INRGSS).

The INRGSS uses tests such as CT, MRI and mIBG scans, as well as blood tests and biopsies, to look at particular details of the cancer. Doctors use this staging system when your child is first diagnosed and before they have surgery.

These details help build up a picture of your child’s cancer. They help your child’s doctor know how difficult the neuroblastoma might be to treat. For example, whether the cancer is wrapped around an organ or large blood vessel. These details are called image defined risk factors (IDRF).

International Neuroblastoma Risk Group Staging System (INRGSS)

Stage L1

The cancer is in one area of the body and hasn’t spread anywhere. It is possible to remove the cancer completely with surgery.

Stage L2

The cancer is in one area of the body, but has started to spread. Tests show at least one or more image defined risk factors. Because of these factors it is not possible to remove the cancer with surgery safely.

Stage M

The cancer has spread to distant parts of the body from where it started.

Stage MS

Your child is less than 12 months old, and the cancer has spread to one or more of the following areas, the:

• skin

• liver

• bone marrow

But the cancer has not spread to the bone, lung or central nervous system.

Neuroblastoma risk groups

Doctors take into account a number of different things when deciding on a risk group. It’s likely that as our understanding of neuroblastoma develops, doctors will add or take factors out, to keep the risk groups up to date.

Age

Age affects risk groups, the following are generally lower risk:

• infants from the age of 2 months

• children who are younger than 12 to 18 months

What the cancer looks like under a microscope (histology)

By looking at the cancer under a microscope pathologists can find out how well developed or mature the cancer cells are compared to normal cells. This is known as differentiation.

For example, tumours that haven’t spread with more normal (mature) looking cells tend to be lower risk.

Stage

The size of the cancer and whether it has spread.

Gene and chromosome changes

A gene called ​MYCN​ controls cell growth. Some neuroblastoma tumours have too many of these genes. This means that the cells grow quickly and are less likely to mature. Tumours with too many MYCN genes are nearly always high risk.

Anaplastic lymphoma kinase (ALK) gene is another type of cancer gene. Also known as an oncogene. If changes happen to the ALK gene it can cause neuroblastoma cells to grow and behave abnormally as cancer cells. Although having this gene change doesn’t affect the risk group your child is in, it may change the treatment they have if they have high risk disease and it can be targeted if the neuroblastoma comes back (relapses).

Doctors can look at how much DNA there is in the cells (DNA ploidy). Genes are made of DNA and they are grouped together to make chromosomes. Changes in chromosomes and how much DNA there is in a cell can affect how well treatment works.

Changes in chromosomes means neuroblastoma cells may have extra copies of whole chromosomes. Or they may be missing chromosomes. Sometimes only part of a chromosome is gained or lost.

Doctors use these findings to help determine a child's risk group and guide treatment decisions. So depending on the type of change in the chromosomes, your child may need more treatment. Your child's doctor will talk this through with you.

Treatment for neuroblastoma

We have an overview of treatment for children with neuroblastoma.

Your child’s doctor and specialist nurse will give you a clear individual treatment plan for your child. Ask them as many questions as you need about staging, risk groups and the science of neuroblastoma. It’s very complex and no one would expect you to understand it all.

Read more about treatment for neuroblastoma